Effects of linagliptin on endothelial function and postprandial lipids in coronary artery disease patients with early diabetes: a randomized, placebo-controlled, double-blind trial.

BACKGROUND: Early glucose lowering intervention in subjects with type 2 diabetes mellitus was demonstrated to be beneficial in terms of micro- and macrovascular risk reduction. However, most of currently ongoing cardiovascular outcome trials are performed in subjects with manifest atherosclerosis and long-standing diabetes. Therefore, the aim of this study is to investigate the effects of the dipeptidylpeptidase-4 inhibitor linagliptin in subjects with coronary artery disease (CAD) but early type 2 diabetes mellitus (T2DM) on a set of cardiovascular surrogate measurements. METHODS: In this randomized, placebo-controlled, double-blind, single-center study, we included subjects with early diabetes (postchallenge diabetes (2 h glucose > 200 mg/dl) or T2DM treated with diet only or on a stable dose of metformin monotherapy and an HbA1c < 75 mmol/mol) and established CAD. Participants were randomized to receive either linagliptin (5 mg) once daily orally or placebo for 12 weeks. The primary outcome was the change in flow mediated dilatation (FMD). The secondary objective was to investigate the effect of linagliptin treatment on arginine bioavailability ratios [Global arginine bioavailability ratio (GABR) and arginine to ornithine ratio (AOR)]. Arginine, ornithine and citrulline were measured in serum samples with a conventional usual amino acid analysis technique, involving separation of amino acids by ion exchange chromatography followed by postcolumn continuous reaction with ninhydrin. GABR was calculated by L-arginine divided by the sum of (L-ornithine plus L-citrulline). The AOR was calculated by dividing L-arginine by L-ornithine levels. Group comparisons were calculated by using a two-sample t-test with Satterthwaite adjustment for unequal variances. RESULTS: We investigated 43 patients (21% female) with a mean age of 63.3 ± 8.2 years. FMD at baseline was 3.5 ± 3.1% in the linagliptin group vs. 4.0 ± 2.9% in the placebo group. The change in mean FMD in the linagliptin group was not significantly different compared to the change in the placebo group (0.43 ± 4.84% vs. - 0.45 ± 3.01%; p = 0.486). No significant improvements were seen in the arginine bioavailability ratios (GABR; p = 0.608 and AOR; p = 0.549). CONCLUSION: Linagliptin treatment in subjects with CAD and early T2DM did not improve endothelial function or the arginine bioavailability ratios. Trial registration ClinicalTrials.gov, NCT02350478 ( https://clinicaltrials.gov/ct2/show/NCT02350478 ).

Impact of Duodeno-Jejunal Bypass Liner (EndoBarrierTM) Implantation on Insulin Sensitivity in Patients with Type 2 Diabetes Mellitus (T2DM): A Study Protocol for a Pilot Trial.

INTRODUCTION: A 60-cm endoscopically implantable duodenal-jejunal bypass liner (Endobarrier™, GI Dynamics, Lexington, MA, USA) has been introduced as a therapeutic option to support weight loss for a selected group of obese subjects with type 2 diabetes mellitus (T2DM). The sleeve prevents contact between chyme and the intestinal mucosa of the upper gastrointestinal tract. The primary aim of this study is to elucidate the changes in insulin sensitivity and beta-cell function after EndoBarrier™ implantation in obese patients with T2DM; changes in gut permeability and gut microbiome are also to be examined. METHODS: This is an open, single-center, prospective trial in which ten obese subjects with T2DM and suboptimal glycemic control (glycosylated hemoglobin A1c (HbA1c) level > 48 mmol/mol) are investigated with regards to EndoBarrier™ implantation. The Endobarrier™ is implanted shortly after baseline and left in situ for a period of 36 weeks. Dual-energy X-ray absorptiometry measurement, assessment of beta-cell function and insulin sensitivity as measured by a Botnia clamp procedure, and a mixed-meal tolerance test are performed prior to implantation and at 4, 36, and 64 weeks after implantation. The composition of the gut microbiota is characterized from stool using 454 pyrosequencing of 16S rRNA genes. Gut permeability is assessed by a differential sugar absorption method. PLANNED OUTCOME: This study will give mechanistic insights in particulr into changes of insulin sensitivity, beta-cell function or microbiome changes over time in subjects implanted with an EndobarrierTM device. TRIAL REGISTRATION: NCT02769728, Registered 12 May 2016. Current Protocol Date/Version: 04 September 2017/Version 1.9.

Alternate Day Fasting Improves Physiological and Molecular Markers of Aging in Healthy, Non-obese Humans.

Caloric restriction and intermittent fasting are known to prolong life- and healthspan in model organisms, while their effects on humans are less well studied. In a randomized controlled trial study (ClinicalTrials.gov identifier: NCT02673515), we show that 4 weeks of strict alternate day fasting (ADF) improved markers of general health in healthy, middle-aged humans while causing a 37% calorie reduction on average. No adverse effects occurred even after >6 months. ADF improved cardiovascular markers, reduced fat mass (particularly the trunk fat), improving the fat-to-lean ratio, and increased ß-hydroxybutyrate, even on non-fasting days. On fasting days, the pro-aging amino-acid methionine, among others, was periodically depleted, while polyunsaturated fatty acids were elevated. We found reduced levels sICAM-1 (an age-associated inflammatory marker), low-density lipoprotein, and the metabolic regulator triiodothyronine after long-term ADF. These results shed light on the physiological impact of ADF and supports its safety. ADF could eventually become a clinically relevant intervention.

Intermittent Fasting (Alternate Day Fasting) in Healthy, Non-obese Adults: Protocol for a Cohort Trial with an Embedded Randomized Controlled Pilot Trial.

BACKGROUND/OBJECTIVES: Alternate day fasting (ADF) is a subtype of intermittent fasting and is defined as a continuous sequence of a fast day (100% energy restriction, zero calories) and a feed day (ad libitum food consumption), resulting in roughly 36-h fasting periods. Previous studies demonstrated weight reductions and improvements of cardiovascular risk factors with ADF in obese subjects. However, rigorous data on potential endocrine, metabolic and cardiovascular effects, besides weight loss, are lacking. Therefore we aim to investigate the short- and mid- to long-term clinical and molecular effects of ADF in healthy non-obese subjects. METHODS: We will perform a prospective cohort study with an embedded randomized controlled trial (RCT) including 90 healthy subjects. Thirty of them will have performed ADF for at least 6 months (mid-term group). Sixty healthy subjects without a particular diet before enrolment will serve as the control group. These subjects will be 1:1 randomized to either continuing their current diet or performing ADF for 4 weeks. All subjects will undergo study procedures that will be repeated in RCT participants after 4 weeks. These procedures will include assessment of outcome parameters, dual-energy X-ray absorptiometry, measurement of endothelial function, an oral glucose tolerance test, 24-h blood pressure measurement, retinal vessel analysis, echocardiography and physical activity measurement by an accelerometer. Blood, sputum, buccal mucosa and faeces will be collected for laboratory analyses. Participants in the RCT will wear a continuous glucose monitor to verify adherence to the study intervention. PLANNED OUTCOMES: The aim of this project is to investigate the effects of ADF on human physiology and molecular cellular processes. This investigation should gain in-depth mechanistic insights into the concept of ADF and form the basis for larger subsequent cohort recruitment and consecutive intervention studies. TRIAL REGISTRATION: NCT02673515; registered 24 November 2015. Current protocol date/version: 7 February 2017/version 1.8.

The effects of linagliptin on endothelial function and global arginine bioavailability ratio in coronary artery disease patients with early diabetes: study protocol for a randomized controlled trial.

BACKGROUND: Patients with type 2 diabetes (T2DM) are at increased risk for macrovascular events as well as for microvascular complications. There is evidence that in patients with coronary artery disease (CAD), about 35 % suffer from manifest T2DM. Early glucose-lowering intervention in subjects with T2DM has been demonstrated to be beneficial in terms of cardiovascular risk reduction. But thus far, no data are available regarding investigating the impact of linagliptin treatment in patients with early diabetes on cardiovascular endpoints or surrogate parameters. Therefore, the aim of this study is to investigate the effects of linagliptin in CAD patients with early T2DM on various cardiovascular surrogate measurements including mechanical and biochemical endothelial function assessments. METHODS/DESIGN: Forty-two subjects with early diabetes and CAD are included in this investigator-driven, randomized, placebo-controlled, double-blind, phase IV, single-center study. Participants will be randomized to receive either linagliptin (5 mg) administered once daily per os or placebo for 12 weeks. Before and after the intervention, evaluation of endothelial function (flow-mediated dilatation and biochemical biomarkers) and a Meal Tolerance Test are performed. DISCUSSION: Cardiovascular surrogate parameters, such as endothelial function, are able to provide insights into the potential mechanisms of the cardiovascular effects of antihyperglycemic agents. Currently ongoing trials do not specifically focus on early diabetes as a target of intervention and we therefore believe that our study will contribute to a better understanding of the cardiovascular effects of dipeptidylpeptidase-4 (DPP-4) inhibitors in early diabetes. TRIAL REGISTRATION: NCT02350478 . Registered 26 January 2015. Protocol date/version 24 October 2014/version 2.4 EudraCT number: 2013-000330-35.